Tag Archives: Heike Ebendorff-Heidepriem

A novel, high sensitivity Sagnac-interferometer biosensor

30 April 2018:

A new publication featuring CNBP co-authors (Dr Stephen Warren-Smith pictured left and Prof Heike Ebendorff-Heidepriem) reports on the design and implementation of a novel, high sensitivity Sagnac-interferometer biosensor based on an exposed core microstructured optical fiber (ECF).

Journal: Sensors and Actuators B: Chemical.

Publication title: High-sensitivity Sagnac-interferometer biosensor based on exposed core microstructured optical fiber.

Authors: Xuegang Li, Linh V. Nguyen, Yong Zhao, Heike Ebendorff-Heidepriem, Stephen C. Warren-Smith.

Abstract: A novel, high sensitivity Sagnac-interferometer biosensor based on exposed core microstructured optical fiber (ECF) has been designed and implemented in this paper. The exposed core fiber has noncircular symmetry and thus exhibits birefringence and can form a sensing element within a Sagnac loop interferometer. The exposed-core fiber design provides direct access to the evanescent field, allowing the measurement of bulk refractive index (RI) with a sensitivity of up to −3137 nm/RIU while maintaining the fiber’s robustness. The sensor can also detect the localized refractive index changes at the fiber core’s surface as the result of a biological binding event. We demonstrate the use of this sensor for label-free sensing of biological molecules by immobilizing biotin onto the fiber core as the probe to capture the target molecule streptavidin.

Sensors for calcium ion

15 June 2017:

Researchers from CNBP (lead author Dr Sabrina Heng pictured), have just had a paper published, reporting on three new spiropyran-based reversible sensors for calcium ion.

Journal: Sensors and Actuators B: Chemical.

Publication title: Photoswitchable calcium sensor: ‘On’–‘Off’ sensing in cells or with microstructured optical fibers.

Authors: Sabrina Heng, Adrian M. Mak, Roman Kostecki, Xiaozhou Zhang, Jinxin Peia, Daniel B. Stubing, Heike Ebendorff-Heidepriema, Andrew D. Abell.

Abstract: Calcium is a ubiquitous intracellular signaling ion that plays a critical role in the modulation of fundamental cellular processes. A detailed study of these processes requires selective and reversible sensing of Ca2+ and an ability to quantify and monitor concentration changes in a biological setting. Three new, rationally designed, synthesized and photoswitchable spiropyran-based reversible sensors for Ca2+ are reported. Sensor 1a is highly selective for Ca2+ with an improved profile relative to the other two analogues, 1b and 1c. Formation of the merocyanine–Ca2+ complex is proportional to an increase in Ca2+ released from HEK293 cells on stimulation with ionomycin. The photophysical processes surrounding the binding of Ca2+ to compound 1a were further explored using computational methods based on density functional theory (DFT). The ability of sensor 1a to bind Ca2+ and photoswitch reversibly was also characterized using silica suspended-core microstructured optical fiber (SCF). These SCF experiments (with 100 nM Ca2+) represent a first step toward developing photoswitchable, minimally invasive and highly sensitive Ca2+ sensing platforms for use in a biological setting.

The paper is accessible online.

CNBP talks to the pollies at SmP

24 March 2017:

A chance to talk science with Australian politicians and policy influencers was an opportunity seized by CNBP with Centre Investigator Prof Heike Ebendorff-Heidepriem and Centre Research Fellow Dr Andrew Care both in attendance at the annual ‘Science meets Parliament’ (SmP) event, Canberra, 21-22 March, 2017.

Established by Science and Technology Australia, SmP provides 200 scientists with a unique professional development opportunity to get a clear sense of the competing rationalities of science, politics and public policy. The two-day gathering also includes a day at Parliament House, where delegates get the chance to meet privately with parliamentarians.

As part of this activity, Prof Ebendorff-Heidepriem met with Senator Chris Back and Senator Chris Ketter, and also spoke with Shadow Minister of Defence, Richard Marles. In addition, she spoke with many researchers and entrepreneurs from both the University and industry sectors.

“Improving collaboration between the research community and industry was a hot topic in many of the discussions that I had”, said Heike. “Particularly in my meeting with Senator Chris Back. People were also extremely excited about our approach, in using fibres and light to create exciting new windows into the body.”

CNBP’s Dr Andrew Care met with Opposition Leader Bill Shorten’s advisor, discussing gender equality and early education for STEM and also touching on ECR opportunities and improving research and industry ties. He also met MP Adam Bandt, the Greens spokesperson for science.

“Overall it was an extremely rewarding experience,” says Andrew. “Attending SmP gave me the opportunity to explore the political process and to network with many other researchers from academia, industry, and governance. It was fantastic to see science and innovation so high on the government’s agenda.”

A full round up from both days of SmP can be found on the STA web site – Day 1 and Day 2.

Below – MP Adam Bandt and CNBP’s Dr Andrew Care.

 

Sensing Zn2+ ions in biological samples

sabrina213 May 2016:

CNBP researchers have created nanoscale biosensors that are capable of sensing Zn2+ ions in biological samples. Such sensors have potential application in disease diagnosis and study, as well as in environmental sensing. The study was published in the journal ACS Applied Materials and Interfaces, May 13th, 2016.

Publication title: Microstructured Optical Fiber-based Biosensors: Reversible and Nanoliter-Scale Measurement of Zinc Ions.

Authors: Sabrina Heng (pictured), Christopher A. McDevitt, Roman Kostecki, Jacqueline R. Morey, Bart A. Eijkelkamp, Heike Ebendorff-Heidepriem, Tanya M. Monro, and Andrew D. Abell.

Abstract:
Sensing platforms that allow rapid and efficient detection of metal ions would have applications in disease diagnosis and study, as well as environmental sensing. Here, we report the first microstructured optical fiber-based biosensor for the reversible and nanoliter-scale measurement of metal ions. Specifically, a photoswitchable spiropyran Zn2+ sensor is incorporated within the microenvironment of a liposome attached to microstructured optical fibers (exposed-core and suspended-core microstructured optical fibers). Both fiber-based platforms retains high selectivity of ion binding associated with a small molecule sensor, while also allowing nanoliter volume sampling and on/off switching. We have demonstrated that multiple measurements can be made on a single sample without the need to change the sensor. The ability of the new sensing platform to sense Zn2+ in pleural lavage and nasopharynx of mice was compared to that of established ion sensing methodologies such as inductively coupled plasma mass spectrometry (ICP-MS) and a commercially available fluorophore (Fluozin-3), where the optical-fiber-based sensor provides a significant advantage in that it allows the use of nanoliter (nL) sampling when compared to ICP-MS (mL) and FluoZin-3 (μL). This work paves the way to a generic approach for developing surface-based ion sensors using a range of sensor molecules, which can be attached to a surface without the need for its chemical modification and presents an opportunity for the development of new and highly specific ion sensors for real time sensing applications.

The paper is available online.

Drawing tubular fibres

Heike Ebendorff Low Res Edit 018015 December 2015:

CNBP researchers A/Prof Heike Ebendorff-Heidepriem and Dr Herbert Foo feature in this latest paper published in Optical Materials Express – ‘Drawing tubular fibres: experiments versus mathematical modelling.’

Abstract – 
A series of six experiments drawing tubular fibres are compared to some recent mathematical modelling of this fabrication process. The importance of fibre tension in determining the internal geometry of the fibre is demonstrated, confirming a key prediction of the models. There is evidence of self-pressurisation of the internal channel, where an additional pressure is induced in the internal channel as the fibre is drawn, and the dependence of the magnitude of this pressure on fibre tension is discussed. Additionally, there is evidence that the difference between the glass and furnace temperatures is proportional to the furnace temperature and dependent on the preform geometry.

Further paper information is available online.